CN111836577A

CN111836577A - Contact state detection device and wearable equipment

Info

Publication number: CN111836577A
Application number: CN202080001574.4A
Authority: CN
Inventors: 刘畅; 邓福建
Original assignee: Shenzhen Goodix Technology Co Ltd
Current assignee: Shenzhen Goodix Technology Co Ltd
Priority date: 2020-02-03
Filing date: 2020-02-03
Publication date: 2020-10-27
Anticipated expiration: 2040-02-03
Also published as: EP3949833B1; EP3949833A4; CN111836577B; US20220047199A1; WO2021155488A1; EP3949833A1; KR20210145212A

Abstract

Provided are a contact state detection device and a wearable apparatus, the contact state detection device including: the device comprises a first electrode and a second electrode, wherein the first electrode and the second electrode are used for receiving an alternating current signal and a first signal to output a differential signal, the differential signal comprises the first signal and a second signal, the first signal is a detection signal of physiological information of a measured object, and the second signal is a signal formed by modulating the alternating current signal through the first electrode and the second electrode; the sampling circuit is connected to the first electrode and the second electrode, and is used for sampling the differential signal to obtain a target sampling signal, wherein the target sampling signal comprises a first sampling signal corresponding to a first signal and a second sampling signal corresponding to a second signal. The contact state monitoring device can reduce the cost on the basis of solving the problem of electrode detection failure caused by high contact resistance or polarization voltage.

Description

Contact state detection device and wearable equipment

Technical Field

The embodiments of the present application relate to the field of electronics, and more particularly, to a contact state detection apparatus and a wearable device.

Background

Electrocardiographic examination has become an important item of modern medical examination as is well known.

In the medical professional equipment for detecting the electrocardiogram, the alarm can be given out under the condition that the leads (clips of hands and feet or suction balls of the chest) fall off by the lead falling-off detection function so as to remind an operator that the leads are not correctly received by a detected object (a human body or other objects), namely the leads fall off.

With the progress of technology, especially the development of semiconductor technology, small-sized electrocardiograph detection products have been widely applied to various portable and even wearable product fields. The wearable device for electrocardio detection cannot replace professional equipment in hospitals, but has an irreplaceable effect in the fields of health monitoring and disease prevention.

However, the wearable product uses a dry electrode with a relatively small area (when the medical professional device is used, physiological saline is applied to the object to be measured to increase the conductivity of the object to be measured), which may cause the contact impedance between the dry electrode and the object to be measured to be extremely high or cause serious impedance mismatch, for example, in the case of a dry skin surface, in these situations, if the conventional lead-off detection scheme of the medical professional device is adopted to detect the electrode contact state of the wearable device, failure may occur or some adverse effects may exist. For example, extremely high contact impedance or polarization voltage may cause false alarms; for another example, the extremely high contact impedance may amplify the flicker noise in the detection signal, and accordingly, the signal-to-noise ratio affecting the electrocardiographic signal is reduced; even so, the extremely high contact impedance may saturate the amplifier, rendering the electrocardiographic detection ineffective. In addition, the lead falling detection scheme in the medical professional equipment has too many devices and correspondingly has too large manufacturing cost, so the lead falling detection scheme can not be applied to wearable equipment for electrode contact state detection generally.

Therefore, there is a need in the art for a contact state detection scheme that can reduce the manufacturing cost while solving the problem of failure in detecting the contact state of the electrode due to high contact resistance or polarization voltage.

Disclosure of Invention

Provided are a contact state detection device and a wearable device, which can reduce the manufacturing cost on the basis of solving the problem of failure in electrode contact state detection caused by high contact resistance or polarization voltage.

In a first aspect, a contact state detection apparatus is provided, which is suitable for a wearable device, and includes:

the device comprises a first electrode and a second electrode, wherein the first electrode and the second electrode are used for receiving an alternating current signal and a first signal to output a differential signal, the differential signal comprises the first signal and a second signal, the first signal is a detection signal of physiological information of a measured object, and the second signal is a signal formed by modulating the alternating current signal through the first electrode and the second electrode;

the sampling circuit is connected to the first electrode and the second electrode and is used for sampling the differential signal to obtain a target sampling signal, and the target sampling signal comprises a first sampling signal corresponding to a first signal and a second sampling signal corresponding to a second signal;

the first sampling signal is used for representing a physiological signal of the measured object, and the second sampling signal is used for detecting a contact state of the first electrode and the measured object and/or a contact state of the second electrode and the measured object.

When the first electrode or the second electrode is in contact with the measured object (the first signal exists), the voltage difference between the first electrode and the second electrode changes, and correspondingly, the differential signal output by the first electrode and the second electrode changes; when the first electrode and/or the second electrode is/are in contact with an object to be measured, the alternating current signal is modulated by the first electrode and the second electrode to form a modulation signal, and the modulation signal is changed relative to the situation that the first electrode and/or the second electrode is/are not in contact with the object to be measured; in this case, the physiological parameter information of the object to be measured can be detected by the first signal in the sampling signal, and on this basis, whether the first electrode or the second electrode is released from the object to be measured can be reflected by the second signal, so that the electrode contact state detection can be performed simultaneously with the physiological information detection.

In addition, the first electrode and the second electrode are driven by the alternating current signal to detect the physiological information of the object to be detected, so that the alternating current signal modulated by the first electrode and the second electrode in the target sampling signal can be multiplexed into a signal for indicating whether the first electrode and/or the second electrode and the object to be detected fall off or not while the physiological information detection is realized, the number of devices in the contact state detection device can be reduced, and accordingly, the device is simplified and the manufacturing cost is reduced.

In some possible implementations, the alternating current signal is a high frequency signal.

Because the detection signal also is the low frequency signal, will alternating current signal constructs for high frequency signal, can distinguish more easily on the one hand first sampling signal in the target sampling signal with the second sampling signal, on the other hand, can reduce alternating current signal is to the interference of detection signal, corresponding, increased the SNR of detection signal.

In some possible implementations, the frequency of the alternating current signal is greater than the frequency of the detection signal.

The frequency of the alternating current signal is configured to be greater (or much greater) than the frequency of the detection signal, so that on one hand, the first sampling signal and the second sampling signal in the target sampling signal can be distinguished more easily, and on the other hand, the interference of the alternating current signal on the detection signal can be reduced, and accordingly, the signal-to-noise ratio of the detection signal is increased.

In some possible implementations, the sampling circuit samples the differential signal at a target phase and a target frequency, the second sampled signal being affected by at least one of: a frequency of the alternating current signal, the target frequency, and the target phase.

Based on factors affecting the second sampled signal (the frequency of the ac signal, the target frequency, and the target phase), a reasonable second sampled signal may be designed or constructed to achieve a desired detection accuracy or precision.

In some possible implementations, the target phase is not equal to an integer multiple of 180 degrees.

The target phase is constructed to be not equal to the integral multiple of 180 degrees, so that the distinguishing difficulty of the first sampling signal and the second sampling signal can be reduced, and correspondingly, the detection effect of the contact state detection device can be improved.

In some possible implementations, the target phase is equal to an integer multiple of 90 degrees.

The target phase is constructed to be equal to the integral multiple of 90 degrees, so that the distinguishing difficulty of the first sampling signal and the second sampling signal is minimum, and correspondingly, the detection effect of the contact state detection device can be effectively improved.

In some possible implementations, the target frequency is greater than or equal to the frequency of the alternating current signal, or a difference between the target frequency and the frequency of the alternating current signal is greater than the frequency of the detection signal.

Through designing the sampling parameter of sampling circuit, can ensure including in the target sampling signal first sampling signal with the second sampling signal, it is corresponding, can increase sampling circuit's sampling effect and promote contact state detection device's detection effect.

In some possible implementations, the target frequency is an integer multiple or a fraction of a frequency of the alternating current signal.

The target frequency is constructed to be integral multiple or fractional multiple of the frequency of the alternating current signal, and compared with the method of sampling the alternating current signal by using a sampling rate which is 4 times or even higher, the power consumption can be effectively reduced, and correspondingly, the endurance time of the wearable device can be increased.

In some possible implementations, the target frequency is greater than or equal to twice the frequency of the alternating current signal.

Configuring the target frequency to be greater than or equal to twice the frequency of the alternating current signal may cause sampling by the sampling circuit to satisfy the nakes sampling law to ensure sampling effect.

In some possible implementations, the contact state detection device further includes:

a first power supply;

wherein the first power supply is connected to the first electrode and the second electrode, respectively, to output the alternating current signal to the first electrode and the second electrode, respectively.

a third electrode for receiving the alternating current signal, wherein signals with equal frequency, amplitude and phase exist between the first electrode and the third electrode and between the second electrode and the third electrode.

By providing a third electrode, which is equivalent to providing one reference electrode for the first electrode and the second electrode, the subsequent signal processing of the differential signal can be simplified, so as to simplify the contact state detection device and reduce the manufacturing cost.

a second power supply and a third power supply;

wherein the second power supply is connected to the first electrode and the third electrode, respectively, and the third power supply is connected to the second electrode and the third electrode, respectively, so that signals having equal frequency, equal amplitude, and equal phase exist between the first electrode and the third electrode and between the second electrode and the third electrode.

the first electrode and the second electrode are connected to the sampling circuit through the analog front end respectively, the analog front end is used for receiving the differential signal and converting the differential signal into a digital signal, and the sampling circuit is used for sampling the digital signal and generating the target sampling signal.

In some possible implementations, the analog front end includes at least one of a filter, a differential amplifier, and an analog-to-digital converter.

a digital processing circuit connected to the sampling circuit, the digital processing circuit to receive the target sampling signal and generate the first and second sampling signals based on the target sampling signal.

In some possible implementations, the digital processing circuit is connected to a master controller of the wearable device, the master controller being configured to control operations of various modules in the wearable device; the main controller is further configured to receive the second sampling signal and determine whether to output an early warning signal based on the second sampling signal, or the main controller is configured to receive the early warning signal sent by the digital processing circuit, where the early warning signal is used to indicate that the first electrode or the second electrode and the object to be measured are in a falling state.

In a second aspect, an electronic device is provided, comprising:

the contact state detection device according to the first aspect or any one of possible implementations of the first aspect.

Drawings

Fig. 1 is a schematic configuration diagram of a contact state detection device according to an embodiment of the present application.

Fig. 2 is a schematic configuration diagram of the positional relationship between the first electrode and the second electrode and the object to be measured, respectively, in the contact state detection device according to the embodiment of the present application.

Fig. 3 is a schematic configuration diagram of a contact state detection apparatus including a third electrode according to an embodiment of the present application.

Fig. 4 and 5 are schematic diagrams each showing an equivalent circuit formed by an electrode and a measured object in the contact state detection device according to the embodiment of the present application.

Fig. 6 is a schematic configuration diagram of transmission signals between respective devices in the contact state detecting apparatus shown in fig. 1.

Detailed Description

The technical solutions in the embodiments of the present application will be described below with reference to the accompanying drawings.

Fig. 1 is a schematic configuration diagram of a contact state detection apparatus 100 according to an embodiment of the present application. It should be understood that the contact state detection apparatus 100 may be applied to wearable devices including, but not limited to, health bracelet/watch, heart rate bracelet/watch, bluetooth headset, wired headset, handheld device, and the like. It should also be understood that the contact state detection apparatus 100 may be applied to any electronic device that needs to detect the contact state between an electrode and an object to be measured. For example, the electronic device may be a medical electrocardiograph detection device, and the contact state detection apparatus 100 may be configured to detect a contact state between an electrode of the medical electrocardiograph detection device and a detected object (e.g., a human body) to determine whether the electrode is detached, that is, the contact state detection apparatus 100 may be an electrode contact state detection apparatus or an electrode detachment detection apparatus.

As shown in fig. 1, the contact state detection apparatus 100 may include a first electrode 111 and a second electrode 112, where the first electrode 111 and the second electrode 112 are configured to receive an alternating current signal and a first signal to output a differential signal, where the differential signal includes the first signal and a second signal, the first signal is a detection signal of physiological information of an object 110 to be detected, and the second signal is a signal formed by modulating the alternating current signal via the first electrode 111 and the second electrode 112; the contact state detection apparatus 100 may further include a sampling circuit 121, where the sampling circuit 121 is connected to the first electrode 111 and the second electrode 112, and the sampling circuit 121 is configured to sample the differential signal to obtain a target sampling signal, where the target sampling signal includes a first sampling signal corresponding to the first signal and a second sampling signal corresponding to the second signal.

The first sampling signal is used to represent a physiological signal of the object to be measured 110, and the second sampling signal is used to detect a contact state of the first electrode 111 and the object to be measured 110 and/or a contact state of the second electrode 112 and the object to be measured 110.

The sampling circuit 121 may perform correlated sampling (i.e., sampling in which an ADC sampling frequency and an ADC sampling phase satisfy a predetermined relationship) on a signal (e.g., the differential signal) through an analog-to-digital converter (ADC), and sampling data (i.e., the target sampling signal) of the ADC may be used to perform computational analysis to extract impedance information between the first electrode 111 and/or the second electrode 112 and the object 110 to be measured, so as to determine a contact state between the first electrode 111 and/or the second electrode 112 and the object 110 to be measured.

In other words, the sampling circuit 121 may include an analog-to-digital converter for sampling the differential signal to obtain a target sampling signal.

When the first electrode 111 or the second electrode 112 is in contact with the object 110 to be measured (the first signal exists), the voltage difference between the first electrode 111 and the second electrode 112 changes, and accordingly, the differential signal output by the first electrode 111 and the second electrode 112 changes. In other words, when the first electrode 111 and/or the second electrode 112 is in contact with the object 110 to be measured, the modulation signal formed by modulating the ac signal with the first electrode 111 and the second electrode 112 may be changed relative to when the first electrode 111 and/or the second electrode 112 is not in contact with the object 110 to be measured. In this case, the physiological parameter information of the object 110 to be measured can be detected by the first signal in the sampling signal, and in addition, whether the first electrode 111 or the second electrode 112 is in contact with the object 110 to be measured can be reflected by the second signal, so that the electrode contact state detection can be performed simultaneously with the physiological information detection.

For example, the contact state between the first electrode 111 and/or the second electrode 112 and the object 110 to be measured may be determined by comparing the amplitude (or the reduction amount of the amplitude) of the second signal with a preset threshold. Optionally, the preset threshold may be an amplitude of the second signal in a non-contact state between the first electrode 111 and/or the second electrode 112 and the object 110 to be measured. Optionally, when the amplitude of the second signal is greater than or equal to a preset amplitude, the first electrode 111 or the second electrode 112 and the object 110 to be measured are in a non-contact state. For example, when the positive amplitude of the second signal is greater than or equal to a first threshold, the first electrode 111 and the object to be measured 110 are in a non-contact state, and when the absolute value of the negative amplitude of the second signal is greater than or equal to a second threshold, the second electrode 112 and the object to be measured 110 are in a non-contact state. The first threshold and the second threshold may be equal or unequal. Optionally, the first threshold and the second threshold may be thresholds for electrode contact state detection by the wearable device. Optionally, the first threshold and the second threshold may be greater than a threshold for lead contact status detection by the medical-specific apparatus to avoid false detection due to high contact impedance.

In addition, by driving the first electrode 111 and the second electrode 112 by the ac signal to detect the physiological information of the object to be detected 110, while realizing the detection of the physiological information, the ac signal modulated by the first electrode 111 and the second electrode 112 in the target sampling signal can be multiplexed into a signal indicating the contact state of the first electrode 111 and/or the second electrode 112 and the object to be detected 110, such as a signal indicating whether the first electrode 111 and/or the second electrode 112 is detached, which can reduce the number of devices in the contact state detection apparatus 100, and accordingly, simplify the apparatus and reduce the manufacturing cost.

In addition, the sampling parameters of the sampling circuit 121 may be designed to improve the sampling effect of the sampling circuit 121 on the differential signal.

In some embodiments of the present application, the sampling circuit 121 may sample the differential signal at a target phase and a target frequency, and the second sampling signal is affected by at least one of the following factors: a frequency of the alternating current signal, the target frequency, and the target phase.

For example, the signal type of the second sampled signal is affected by at least one of the following factors: a frequency of the alternating current signal, the target frequency, and the target phase. Optionally, the type of the second sampling signal includes, but is not limited to, a direct current signal type and an alternating current signal type, and the alternating current signal type includes, but is not limited to, alternating current signals of different frequencies. For example, if the target phase is an integer multiple of 90 degrees and the target frequency is equal to the frequency of the ac signal, the first sampling signal is a dc signal; and if the target phase is an integral multiple of 90 degrees and the target frequency is not equal to the frequency of the alternating current signal, the first sampling signal is an alternating current signal.

In other words, based on the circuit structure among the first electrode 111, the second electrode 112, and the sampling circuit 121 in the present application, the ac signal for driving the first electrode 111 and the second electrode 112 and the sampling parameter of the sampling circuit 121 may be designed to obtain the desired second sampling signal.

For example, the target phase is not equal to an integer multiple of 180 degrees, so that the difficulty in distinguishing the first sampling signal from the second sampling signal can be reduced, and accordingly, the detection effect of the contact state detection apparatus 100 can be improved. For another example, the target phase is equal to an integer multiple of 90 degrees, so that the difficulty in distinguishing the first sampling signal from the second sampling signal can be minimized, and accordingly, the detection effect of the contact state detection device can be effectively improved. Alternatively, the target phase may be a phase at which the sampling circuit 121 samples the differential signal when the phase of the alternating current signal is zero.

For another example, the target frequency is greater than or equal to the frequency of the alternating current signal, or the difference between the target frequency and the frequency of the alternating current signal is greater than the frequency of the detection signal. Accordingly, the target sampling signal can be ensured to include the first sampling signal and the second sampling signal, and accordingly, the sampling effect of the sampling circuit 121 can be increased and the detection effect of the contact state detection apparatus 100 can be improved. Optionally, the target frequency is an integer multiple or a fraction multiple of the frequency of the alternating current signal. For example, the target frequency is greater than or equal to twice the frequency of the alternating current signal. Configuring the target frequency to be greater than or equal to twice the frequency of the alternating current signal makes it possible to cause the sampling by the sampling circuit 121 to satisfy the nakes sampling law to ensure the sampling effect.

In addition, the alternating current signal can be designed to increase the signal-to-noise ratio of the detection signal.

For example, the alternating current signal is a high frequency signal. Because the detection signal is the low frequency signal, will alternating current signal constructs for high frequency signal, can distinguish more easily on the one hand first sampling signal in the target sampling signal with the second sampling signal, on the other hand, can reduce alternating current signal is to the interference of detection signal, it is corresponding, increased the SNR of detection signal.

For another example, the frequency of the alternating current signal is greater than the frequency of the detection signal. By configuring the frequency of the alternating current signal to be greater (or much greater) than the frequency of the detection signal, on one hand, the first sampling signal and the second sampling signal in the target sampling signal can be distinguished more easily, and on the other hand, the interference of the alternating current signal to the detection signal can be reduced, and accordingly, the signal-to-noise ratio of the detection signal is increased.

As shown in fig. 1, in some embodiments of the present application, the contact state detection apparatus 100 may further include a third electrode 113, the third electrode 113 is configured to receive the ac signal, and signals having equal frequency, equal amplitude, and equal phase exist between the first electrode 111 and the third electrode 113 and between the second electrode 112 and the third electrode 113.

By providing the third electrode 113, which is equivalent to providing one reference electrode for the first electrode 111 and the second electrode 112, the subsequent signal processing of the differential signal can be simplified, so as to simplify the contact state detection apparatus 100 and reduce the manufacturing cost.

As shown in fig. 1, in some embodiments of the present application, the contact state detecting device 100 may further include an ac signal source 124, the ac signal source 124 is connected to the first electrode 111 and the second electrode 112, and the ac signal source 124 is configured to generate the ac signal. Alternatively, the ac signal source 124 may be a current source or a voltage source. Alternatively, the alternating current signal may be a sine wave or a square wave.

As shown in fig. 1, in some embodiments of the present application, the contact state detection apparatus 100 further includes an analog front end 122, the first electrode 111 and the second electrode 112 are respectively connected to the sampling circuit 121 through the analog front end 122, the analog front end 122 is configured to receive the differential signal and convert the differential signal into a digital signal, and the sampling circuit 121 is configured to sample the digital signal and generate the target sampling signal.

For example, the analog front end 122 includes at least one of a filter, a differential amplifier, and an analog-to-digital converter. Specifically, the filter filters out a noise signal in the received signal, the differential amplifier differentially amplifies the received differential signal, and the analog-to-digital converter converts the amplified signal into a digital signal, so that the sampling circuit 121 can sample the digital signal and output a target sampling signal.

As shown in fig. 1, in some embodiments of the present application, the contact state detecting device 100 further includes a digital processing circuit 123, the digital processing circuit 123 is connected to the sampling circuit 121, and the digital processing circuit 123 is configured to receive the target sampling signal and generate the first sampling signal and the second sampling signal based on the target sampling signal.

As shown in fig. 1, in an actual product, the ac signal source 124, the analog front end 122, the sampling circuit 121, and the digital processing circuit 123 may be used as devices in the sensor 120 to increase the integration level of the contact state detection device, and accordingly, the occupied volume of the contact state detection device is reduced, thereby improving the applicability of the contact state detection device in a wearable device.

As shown in fig. 1, in some embodiments of the present application, the digital processing circuit 123 is connected to a main controller 130 of the wearable device, and the main controller 130 is used for controlling operations of various modules in the wearable device; the main controller 130 is further configured to receive the second sampling signal and determine whether to output an early warning signal based on the second sampling signal, or the main controller 130 is configured to receive the early warning signal sent by the digital processing circuit, where the early warning signal is used to indicate that the first electrode 111 or the second electrode 112 and the object to be measured 110 are in a falling state.

Fig. 2 and 3 are schematic structural views of the positional relationship between the electrode and the object to be measured in the embodiment of the present application.

As shown in fig. 2, if the contact state detection device 100 includes only the first electrode 111 and the second electrode 112, both the first electrode 111 and the second electrode 112 are in contact with the object 110 to be measured.

As shown in fig. 3, if the contact state detection device 100 further includes a third electrode 113, both the first electrode 111 and the second electrode 112 are in contact with the object 110 to be measured. The third electrode 113 may be in contact with the object 110 to be measured, or may not be in contact with the object 110 to be measured.

As shown in fig. 4, in some embodiments of the present application, the contact state detection apparatus 100 further includes a first power source 1151, and the first power source 1151 is respectively connected to the first electrode 111 and the second electrode 112 to respectively output the alternating current signal to the first electrode 111 and the second electrode 112. A first resistor 1152 and a first capacitor 1153 are formed between the first electrode 111 and the object to be measured.

In other words, an equivalent circuit formed by the first electrode 111, the second electrode 112, and the first power supply 1151 can be described as: one terminal of the first power supply 1151 is connected to the first electrode 111, the other terminal of the first power supply 1151 is connected to the second electrode 112, the first electrode 111 is connected to the second electrode 112 through the first resistor 1152, and the first capacitor 1153 is connected in parallel to the first resistor 1152.

As shown in fig. 5, in other embodiments of the present application, the contact state detecting apparatus 100 further includes a second power source 1161 and a third power source 1171, the second power source 1161 is connected to the first electrode 111 and the third electrode 113, respectively, and the third power source 1171 is connected to the second electrode 112 and the third electrode 113, respectively, so that signals with equal frequency, equal amplitude, and equal phase exist between the first electrode 111 and the third electrode 113 and between the second electrode 112 and the third electrode 113.

In other words, an equivalent circuit formed by the first electrode 111, the second electrode 112, the third electrode 113, and the first power supply 1151 can be described as: one end of the third electrode 113 is connected to one end of the first electrode 111 through the second power source 1161 and is connected to one end of the second electrode 112 through the third power source 1171, the other end of the third electrode 113 is connected to the other end of the first electrode 111 through the second resistor 1162 and is connected to the other end of the second electrode 112 through the third resistor 1172, the second capacitor 1163 is connected to the second resistor 1162 in parallel, and the third capacitor 1173 is connected to the third resistor 1172 in parallel.

As shown in fig. 6, in the contact state detection apparatus 100, the first electrode 111 and the second electrode 112 output a differential signal to the analog front end 122 so that the analog front end 122 converts the differential signal into a digital signal, the sampling circuit 121 samples the digital signal with a signal having a target frequency and a target phase to output the target sampling signal, and the digital processing circuit 123 generates a first sampling signal and a second sampling signal based on the target sampling signal and outputs the first sampling signal and the second sampling signal to the main controller 130. Optionally, the digital processing circuit 123 may further generate the warning signal based on the second sampling signal, and output the warning signal to the main controller 130.

In addition, the present application provides a wearable device, which may include the above-described contact state detection apparatus 100.

Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

In addition, functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit.

The functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application or portions thereof that substantially contribute to the prior art may be embodied in the form of a software product stored in a storage medium and including instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present application. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A contact state detection device, characterized by comprising:

2. The contact state detection device according to claim 1, wherein the alternating current signal is a high frequency signal.

3. The contact state detection device according to claim 1 or 2, wherein a frequency of the alternating current signal is larger than a frequency of the detection signal.

4. The contact state detection device according to any one of claims 1 to 3, wherein the sampling circuit samples the differential signal at a target phase and a target frequency, and the second sampling signal is affected by at least one of: a frequency of the alternating current signal, the target frequency, and the target phase.

5. The contact state detection device according to claim 4, wherein the target phase is not equal to an integer multiple of 180 degrees.

6. The contact state detection device according to claim 4, wherein the target phase is equal to an integer multiple of 90 degrees.

7. The contact state detection device according to claim 4, wherein the target frequency is greater than or equal to the frequency of the alternating current signal, or a difference between the target frequency and the frequency of the alternating current signal is greater than the frequency of the detection signal.

8. The contact state detection device according to claim 7, wherein the target frequency is an integer multiple or a fractional multiple of a frequency of the alternating current signal.

9. The contact state detection device according to claim 7, wherein the target frequency is greater than or equal to twice the frequency of the alternating current signal.

10. The contact state detection device according to any one of claims 1 to 9, characterized by further comprising:

a first power supply;

11. The contact state detection device according to any one of claims 1 to 9, characterized by further comprising:

12. The contact state detection device according to claim 11, characterized by further comprising:

a second power supply and a third power supply;

13. The contact state detection device according to any one of claims 1 to 12, characterized by further comprising:

14. The touch state detection device of claim 13, wherein the analog front end comprises at least one of a filter, a differential amplifier, and an analog-to-digital converter.

15. The contact state detection device according to any one of claims 1 to 14, characterized by further comprising:

16. The contact state detection device of claim 15, wherein the digital processing circuit is connected to a main controller of the wearable device, the main controller being configured to control the operation of various modules in the wearable device; the main controller is further configured to receive the second sampling signal and determine whether to output an early warning signal based on the second sampling signal, or the main controller is configured to receive the early warning signal sent by the digital processing circuit, where the early warning signal is used to indicate that the first electrode or the second electrode and the object to be measured are in a falling state.

17. A wearable device, comprising:

the contact state detecting device according to any one of claims 1 to 16.